APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21)

Comments and questions about the APOD on the main view screen.
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APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21)

Post by APOD Robot » Mon Jul 21, 2014 4:10 am

Image Spacecraft Rosetta Shows Comet has Two Components

Explanation: Why does this comet's nucleus have two components? The surprising discovery that Comet 67P/Churyumov–Gerasimenko has a double nucleus came late last week as ESA's robotic interplanetary spacecraft Rosetta continued its approach toward the ancient comet's core. Speculative ideas on how the double core was created include, currently, that Comet Churyumov–Gerasimenko is actually the result of the merger of two comets, that the comet is a loose pile of rubble pulled apart by tidal forces, that ice evaporation on the comet has been asymmetric, or that the comet has undergone some sort of explosive event. Pictured above, the comet's unusual 5-km sized comet nucleus is seen rotating over the course of a few hours, with each frame taken 20-minutes apart. Better images -- and hopefully more refined theories -- are expected as Rosetta is on track to enter orbit around Comet Churyumov–Gerasimenko's nucleus early next month, and by the end of the year, if possible, land a probe on it.

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Guest

Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

Post by Guest » Mon Jul 21, 2014 4:19 am

No way that can be asymmetric evaporation/assimilation... That is clearly 2 distinct object that have come together and are on the grand journey together. Very cool to see this level of detail of a nucleus, but higher resolution would be nice; and would probably answer lots more questions. Still... AMAZING...

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Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

Post by ta152h0 » Mon Jul 21, 2014 4:30 am

I have a few asimetric ice cubes stuck together in my freezer. Nop impossible to land on. The americans landed NEAR on EROS, a odd shaped rotating object ( and provbably still there )
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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Alex-the-great » Mon Jul 21, 2014 7:47 am

Wow, landing on that will be ESA's new roller coaster attraction.

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Ann » Mon Jul 21, 2014 10:47 am

Space duck by WOOTinator
As Alex Parker said on this page:
Contact binary? Anvil? Boot? No, the morphology is clear: Churyumov-Gerasimenko is a rubber duckie.


:D

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Joules » Mon Jul 21, 2014 11:23 am

Center of rotation/mass is within or near the neck. The smaller lobe must mass near as much as the larger, so composition must be different.
Iron/nickel vs rock+ice or mostly rock vs mostly ice?
From uniform albedo, everything looks to be covered with coat of dust.

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by MargaritaMc » Mon Jul 21, 2014 11:55 am

"In those rare moments of total quiet with a dark sky, I again feel the awe that struck me as a child. The feeling is utterly overwhelming as my mind races out across the stars. I feel peaceful and serene."
&mdash; Dr Debra M. Elmegreen, Fellow of the AAAS

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by saturno2 » Mon Jul 21, 2014 11:59 am

Object very interesting

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Till Credner » Mon Jul 21, 2014 12:18 pm

No way! It is Santa Claus, who lost one of his boots.

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by neufer » Mon Jul 21, 2014 12:42 pm

Joules wrote:
Center of rotation/mass is within or near the neck. The smaller lobe must mass near as much as the larger, so composition must be different.
Iron/nickel vs rock+ice or mostly rock vs mostly ice?
It's not that clear to me that "the duck's head" is necessarily "the smaller lobe" volume-wise.
Joules wrote:
From uniform albedo, everything looks to be covered with coat of dust.
  • Or is 67P covered with snow:
http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko wrote:
On 6 June 2014 water vapor was detected being released from 67P at a rate of roughly 1 litre per second.
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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by NGC3314 » Mon Jul 21, 2014 1:08 pm

Joules wrote:Center of rotation/mass is within or near the neck.
Im not sure we know that from this image series. They may have been arbitrarily recentered for display at a central position.

tomatoherd

Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by tomatoherd » Mon Jul 21, 2014 1:13 pm

Why do we need a theory as to why it is this shape? Conglomerate ice-rock chunks on earth's surface are any and every shape imaginable. This should be no surprise. At that small size, we'd have a lot more explaining to do if it looked closely spherical.....

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Joules » Mon Jul 21, 2014 1:57 pm

NGC3314 wrote:They may have been arbitrarily recentered for display at a central position.
Could be. There's no stars visible to verify the background, so we'll have to wait a few weeks for better imagery.

eSpace

Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by eSpace » Mon Jul 21, 2014 2:21 pm

Just a minor clarification: The actual rotation rate is just over 12 hours rather than a "few hours". Makes a difference when you're trying to put a lander down....

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Post by neufer » Mon Jul 21, 2014 2:35 pm

eSpace wrote:
Just a minor clarification: The actual rotation rate is just over 12 hours rather than a "few hours". Makes a difference when you're trying to put a lander down....
Few (?), a. [OE. fewe, feawe.] Not many; small, limited, or confined in number; -- indicating a small portion of units or individuals constituing a whole; often, by ellipsis of a noun, a few people. "Are not my days few?" Job x. 20.
  • Hamlet, Prince of Denmark Act 1, Scene 3
LORD POLONIUS: Yet here, Laertes! aboard, aboard, for shame!
  • The wind sits in the shoulder of your sail,
    And you are stay'd for. There; my blessing with thee!
    And these few precepts in thy memory
    See thou character. Give thy thoughts no tongue,
    Nor any unproportioned thought his act.
    Be thou familiar, but by no means vulgar.
    Those friends thou hast, and their adoption tried,
    Grapple them to thy soul with hoops of steel;
    But do not dull thy palm with entertainment
    Of each new-hatch'd, unfledged comrade. Beware
    Of entrance to a quarrel, but being in,
    Bear't that the opposed may beware of thee.
    Give every man thy ear, but few thy voice;
    Take each man's censure, but reserve thy judgment.
    Costly thy habit as thy purse can buy,
    But not express'd in fancy; rich, not gaudy;
    For the apparel oft proclaims the man,
    And they in France of the best rank and station
    Are of a most select and generous chief in that.
    Neither a borrower nor a lender be;
    For loan oft loses both itself and friend,
    And borrowing dulls the edge of husbandry.
    This above all: to thine ownself be true,
    And it must follow, as the night the day,
    Thou canst not then be false to any man.
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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by neufer » Mon Jul 21, 2014 2:50 pm

Joules wrote:
NGC3314 wrote:
They may have been arbitrarily re-centered for display at a central position.
Could be. There's no stars visible to verify the background, so we'll have to wait a few weeks for better imagery.
This seems highly unlikely, IMO.

Joules is just wrong in assuming that the flat body segment is that much larger than the big head segment.
Art Neuendorffer

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Chris Peterson » Mon Jul 21, 2014 2:51 pm

tomatoherd wrote:Why do we need a theory as to why it is this shape?
Because the shape can teach us about the history of the body.
Chris

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Psnarf » Mon Jul 21, 2014 2:51 pm

--
Obquote:

QVACK!
QVACK!! QVACK!
-SETI

(Sorry, had to clear my brain of the Bard of Avon, or I'd be reciting that passage all day. -Shakespeare Ear Worm)

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Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

Post by Chris Peterson » Mon Jul 21, 2014 2:52 pm

Guest wrote:No way that can be asymmetric evaporation/assimilation... That is clearly 2 distinct object that have come together and are on the grand journey together.
There is nowhere near enough information available at this point to make that kind of assertion. All of the suggestions remain viable theories.
Chris

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Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

Post by neufer » Mon Jul 21, 2014 3:33 pm

Chris Peterson wrote:
Guest wrote:
No way that can be asymmetric evaporation/assimilation...
That is clearly 2 distinct object that have come together and are on the grand journey together.
There is nowhere near enough information available at this point to make that kind of assertion.
The large number of binary/double asteroids would suggest that this is not an unreasonable assertion.

http://en.wikipedia.org/wiki/90_Antiope
Chris Peterson wrote:
All of the suggestions remain viable theories.
All of the suggestions remain viable hypotheses.
Art Neuendorffer

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Re: APOD: Spacefract Rosetta Shows Comet has... (2014 Jul 21

Post by Chris Peterson » Mon Jul 21, 2014 4:57 pm

neufer wrote:
Chris Peterson wrote:
Guest wrote:
No way that can be asymmetric evaporation/assimilation...
That is clearly 2 distinct object that have come together and are on the grand journey together.
There is nowhere near enough information available at this point to make that kind of assertion.
The large number of binary/double asteroids would suggest that this is not an unreasonable assertion.
"No way that can be asymmetric evaporation/assimilation... " is an unreasonable assertion.
"That is clearly 2 distinct object that have come together and are on the grand journey together" is an unreasonable assertion.

The unreasonableness has nothing to do with the concepts, and everything to do with the force of support they are given in the face of rather limited evidence.
All of the suggestions remain viable hypotheses.
Actually, they are also viable theories.
Chris

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eSpace

Re: Few know and fewer care. - Proverb.

Post by eSpace » Mon Jul 21, 2014 7:20 pm

neufer wrote:
eSpace wrote:
Just a minor clarification: The actual rotation rate is just over 12 hours rather than a "few hours". Makes a difference when you're trying to put a lander down....
Few (?), a. [OE. fewe, feawe.] Not many; small, limited, or confined in number; -- indicating a small portion of units or individuals constituing a whole; often, by ellipsis of a noun, a few people. "Are not my days few?" Job x. 20.
  • Hamlet, Prince of Denmark Act 1, Scene 3
LORD POLONIUS: Yet here, Laertes! aboard, aboard, for shame!
  • The wind sits in the shoulder of your sail,
    And you are stay'd for. There; my blessing with thee!
    And these few precepts in thy memory
    See thou character. Give thy thoughts no tongue,
    Nor any unproportioned thought his act.
    Be thou familiar, but by no means vulgar.
    Those friends thou hast, and their adoption tried,
    Grapple them to thy soul with hoops of steel;
    But do not dull thy palm with entertainment
    Of each new-hatch'd, unfledged comrade. Beware
    Of entrance to a quarrel, but being in,
    Bear't that the opposed may beware of thee.
    Give every man thy ear, but few thy voice;
    Take each man's censure, but reserve thy judgment.
    Costly thy habit as thy purse can buy,
    But not express'd in fancy; rich, not gaudy;
    For the apparel oft proclaims the man,
    And they in France of the best rank and station
    Are of a most select and generous chief in that.
    Neither a borrower nor a lender be;
    For loan oft loses both itself and friend,
    And borrowing dulls the edge of husbandry.
    This above all: to thine ownself be true,
    And it must follow, as the night the day,
    Thou canst not then be false to any man.
Phew!! :)

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by Ron-Astro Pharmacist » Mon Jul 21, 2014 7:51 pm

Sorry Art - Pun intended :)

Lest Phil canst giver' the what for
since thine didn't oft try
then lets harpoon that yellow ducky
then give it a fry.
Make Mars not Wars

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by hlwelborn » Mon Jul 21, 2014 8:47 pm

mezzzzzmerizing.

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Re: APOD: Spacecraft Rosetta Shows Comet has... (2014 Jul 21

Post by distefanom » Mon Jul 21, 2014 10:38 pm

It seems to an Italian's MOZZARELLA:

Image


:lol2: :lol2: :D